How many of you have dogs at home? If you don’t have one at yours, you must have seen them in the neighborhood, or on the street. Have you ever cared to notice how powerful a dog’s sense of smell is?
In fact, dogs have a very strong sense of smell. Compared to the humans, their nose has twenty times more the number of cells that receive the smell of anything.
The internal make-up of their nose and the mucous in it receive different kinds of chemical coming out of different things in the air, and sense the smell coming from them. Some dogs can detect certain organic chemicals at concentrations a hundred times less than people are able to. For some other compounds the dog’s edge may be a factor of a million or more. In police and security works, dogs can detect the smell from natural gas leaks, hidden drugs, explosives, and currency, all at a level that human nose cannot at any cost detect.
Some dogs can even detect smell on glass slides that have just been touched and left outdoors for as much as two weeks, or indoors for as much as a month. They can distinguish between T-shirts worn by two identical twins who ate different foods, or by two non-identical twins who lived in exactly the same environment and ate exactly the same foods.
In fact, a dog has more than 220 million olfactory receptors in its nose, while humans have only 5 million. Because of this keen sense of smell, dogs are able to locate everything from forensic cadaver material to disaster survivors as demonstrated during the terrorist attack on the World Trade Center on September 11, 2001.
A dog’s nose is normally cool and moist. The moisture captures and dissolves molecules in the air and brings them into contact with a special smelling layer inside the nose. Dogs use sniffing to maximize detection of odors. The sniff is actually a disruption of the normal breathing pattern. Sniffing is done through a series of rapid, short inhalations and exhalations.
Today, people use a dog’s keen sense of smell in many ways. Government agencies employ specially trained dogs in search and detection of drugs and illegal agriculture products. During emergencies and accidents, dogs can be used to detect the people, dead or alive, trapped under the rubble. They help the rescue team to find the victims and save their lives. Security forces make special use of dogs and their smelling power to detect people carrying suspicious materials. This requires a long training, because a dog is not naturally interested in such smells.
Some dogs are even believed to detect breast, bladder and lung cancer in humans. They do so by smelling the breaths of such patients. This news is salutary, because this might reduce the need to undergo expensive tests to diagnose such diseases.